Buggy code:
public class MainGameScreen implements Screen { private SpriteBatch batch ; private WorldManager worldManager ; private OrthographicCamera camera ; private Stage stage = new Stage ( ) ; private Skin buttonSkin ; private Skin labelSkin ; private Box2DDebugRenderer physicsRenderer ; private boolean gameOverMenuActive = false ; private float score ; private Label scoreLabel ; private Table gameOverTable ; private Label gameOverScore ; private Label highScoreLabel ; private TextField highScoreField ; private String name = "" ; private final SimpleDateFormat dateFormat = new SimpleDateFormat ( "dd//MM<seq2seq4repair_space>HH:mm:ss" ) ; public MainGameScreen ( final SpriteBatch b ) { } @ Override public void show ( ) { } @ Override public void resume ( ) { } @ Override public void render ( final float delta ) { } private void gameOverScreenSetup ( ) { gameOverTable = new Table ( ) ; Label topText = new Label ( "Game<seq2seq4repair_space>over!" , labelSkin ) ; gameOverScore = new Label ( "" , labelSkin ) ; highScoreLabel = new Label ( "New<seq2seq4repair_space>Highscore!" , labelSkin ) ; highScoreLabel . setVisible ( false ) ; topText . setPosition ( 0 , 0 ) ; TextButton restartButton = new TextButton ( "New<seq2seq4repair_space>game" , buttonSkin ) ; restartButton . setPosition ( 0 , 0 ) ; restartButton . addListener ( new ClickListener ( ) { @ Override public void clicked ( final InputEvent event , final float x , final float y ) { ScoreContainer . addScore ( Math . round ( score ) , name , dateFormat . format ( new Date ( ) ) ) ; ( ( com . badlogic . gdx . Game ) ( Gdx . app . getApplicationListener ( ) ) ) . setScreen ( new MainGameScreen ( batch ) ) ; } } ) ; TextButton menuButton = new TextButton ( "Menu" , buttonSkin ) ; menuButton . setPosition ( 0 , 0 ) ; menuButton . addListener ( new ClickListener ( ) { @ Override public void clicked ( final InputEvent event , final float x , final float y ) { ScoreContainer . addScore ( Math . round ( score ) , name , dateFormat . format ( new Date ( ) ) ) ; EndlessRunner . get ( ) . create ( ) ; } } ) ; Pixmap pixmap = new Pixmap ( 10 , 10 , Format . RGB565 ) ; pixmap . setColor ( WHITE ) ; pixmap . fill ( ) ; buttonSkin . add ( "background" , new com . badlogic . gdx . graphics . Texture ( pixmap ) ) ; TextFieldStyle txtStyle = new TextFieldStyle ( ) ; txtStyle . font = new BitmapFont ( ) ; txtStyle . fontColor = Color . BLACK ; txtStyle . background = buttonSkin . getDrawable ( "background" ) ; highScoreField = new TextField ( "" , txtStyle ) ; highScoreField . setTextFieldListener ( new TextFieldListener ( ) { @ Override public void keyTyped ( final TextField textField , final char c ) { <START_BUG> name = ( name ) + c ; <END_BUG> } } ) ; gameOverTable . setFillParent ( true ) ; gameOverTable . setColor ( BLUE ) ; gameOverTable . setVisible ( false ) ; gameOverTable . add ( highScoreLabel ) . expandX ( ) . width ( 200.0F ) ; gameOverTable . row ( ) ; gameOverTable . add ( topText ) . width ( 200.0F ) ; gameOverTable . row ( ) ; gameOverTable . add ( gameOverScore ) . width ( 200.0F ) ; gameOverTable . row ( ) ; gameOverTable . add ( highScoreField ) . width ( 200.0F ) . height ( 20.0F ) ; gameOverTable . row ( ) ; Table t2 = new Table ( ) ; t2 . add ( restartButton ) . width ( 100.0F ) ; t2 . add ( menuButton ) . width ( 100.0F ) ; gameOverTable . add ( t2 ) ; stage . addActor ( gameOverTable ) ; } private void createScoreLabel ( ) { } private void createDefaultLabelSkin ( ) { } private void createDefaultButtonSkin ( ) { } @ Override public void pause ( ) { } @ Override public void hide ( ) { } @ Override public void resize ( final int width , final int height ) { } @ Override public void dispose ( ) { } }

Fix:
name = textField . getText ( ) ;